
/*
  http://www.npmjs.org/packages/is-buffer
*/
import crypt from './crypt.js';
import { bin, utf8 } from './charenc.js';

var isBuffer, md5;

/*
  http://www.npmjs.org/packages/is-buffer
*/
isBuffer = function (obj) {
  return !!(obj != null &&
    (obj._isBuffer || // For Safari 5-7 (missing Object.prototype.constructor)
      (obj.constructor &&
      typeof obj.constructor.isBuffer === 'function' &&
      obj.constructor.isBuffer(obj))
    ))
};

/*
  http://www.npmjs.org/packages/md5
*/
md5 = function (message, options) {
  // Convert to byte array
  if (message.constructor == String)
    if (options && options.encoding === 'binary')
      message = bin.stringToBytes(message);
    else
      message = utf8.stringToBytes(message);
  else if (message.constructor === Buffer)
    message = Array.prototype.slice.call(message, 0);
  else if (!Array.isArray(message))
    message = message.toString();
  // else, assume byte array already

  var m = crypt.bytesToWords(message),
      l = message.length * 8,
      a =  1732584193,
      b = -271733879,
      c = -1732584194,
      d =  271733878;

  // Swap endian
  for (var i = 0; i < m.length; i++) {
    m[i] = ((m[i] <<  8) | (m[i] >>> 24)) & 0x00FF00FF |
           ((m[i] << 24) | (m[i] >>>  8)) & 0xFF00FF00;
  }

  // Padding
  m[l >>> 5] |= 0x80 << (l % 32);
  m[(((l + 64) >>> 9) << 4) + 14] = l;

  // Method shortcuts
  var FF = md5._ff,
      GG = md5._gg,
      HH = md5._hh,
      II = md5._ii;

  for (var i = 0; i < m.length; i += 16) {

    var aa = a,
        bb = b,
        cc = c,
        dd = d;

    a = FF(a, b, c, d, m[i+ 0],  7, -680876936);
    d = FF(d, a, b, c, m[i+ 1], 12, -389564586);
    c = FF(c, d, a, b, m[i+ 2], 17,  606105819);
    b = FF(b, c, d, a, m[i+ 3], 22, -1044525330);
    a = FF(a, b, c, d, m[i+ 4],  7, -176418897);
    d = FF(d, a, b, c, m[i+ 5], 12,  1200080426);
    c = FF(c, d, a, b, m[i+ 6], 17, -1473231341);
    b = FF(b, c, d, a, m[i+ 7], 22, -45705983);
    a = FF(a, b, c, d, m[i+ 8],  7,  1770035416);
    d = FF(d, a, b, c, m[i+ 9], 12, -1958414417);
    c = FF(c, d, a, b, m[i+10], 17, -42063);
    b = FF(b, c, d, a, m[i+11], 22, -1990404162);
    a = FF(a, b, c, d, m[i+12],  7,  1804603682);
    d = FF(d, a, b, c, m[i+13], 12, -40341101);
    c = FF(c, d, a, b, m[i+14], 17, -1502002290);
    b = FF(b, c, d, a, m[i+15], 22,  1236535329);

    a = GG(a, b, c, d, m[i+ 1],  5, -165796510);
    d = GG(d, a, b, c, m[i+ 6],  9, -1069501632);
    c = GG(c, d, a, b, m[i+11], 14,  643717713);
    b = GG(b, c, d, a, m[i+ 0], 20, -373897302);
    a = GG(a, b, c, d, m[i+ 5],  5, -701558691);
    d = GG(d, a, b, c, m[i+10],  9,  38016083);
    c = GG(c, d, a, b, m[i+15], 14, -660478335);
    b = GG(b, c, d, a, m[i+ 4], 20, -405537848);
    a = GG(a, b, c, d, m[i+ 9],  5,  568446438);
    d = GG(d, a, b, c, m[i+14],  9, -1019803690);
    c = GG(c, d, a, b, m[i+ 3], 14, -187363961);
    b = GG(b, c, d, a, m[i+ 8], 20,  1163531501);
    a = GG(a, b, c, d, m[i+13],  5, -1444681467);
    d = GG(d, a, b, c, m[i+ 2],  9, -51403784);
    c = GG(c, d, a, b, m[i+ 7], 14,  1735328473);
    b = GG(b, c, d, a, m[i+12], 20, -1926607734);

    a = HH(a, b, c, d, m[i+ 5],  4, -378558);
    d = HH(d, a, b, c, m[i+ 8], 11, -2022574463);
    c = HH(c, d, a, b, m[i+11], 16,  1839030562);
    b = HH(b, c, d, a, m[i+14], 23, -35309556);
    a = HH(a, b, c, d, m[i+ 1],  4, -1530992060);
    d = HH(d, a, b, c, m[i+ 4], 11,  1272893353);
    c = HH(c, d, a, b, m[i+ 7], 16, -155497632);
    b = HH(b, c, d, a, m[i+10], 23, -1094730640);
    a = HH(a, b, c, d, m[i+13],  4,  681279174);
    d = HH(d, a, b, c, m[i+ 0], 11, -358537222);
    c = HH(c, d, a, b, m[i+ 3], 16, -722521979);
    b = HH(b, c, d, a, m[i+ 6], 23,  76029189);
    a = HH(a, b, c, d, m[i+ 9],  4, -640364487);
    d = HH(d, a, b, c, m[i+12], 11, -421815835);
    c = HH(c, d, a, b, m[i+15], 16,  530742520);
    b = HH(b, c, d, a, m[i+ 2], 23, -995338651);

    a = II(a, b, c, d, m[i+ 0],  6, -198630844);
    d = II(d, a, b, c, m[i+ 7], 10,  1126891415);
    c = II(c, d, a, b, m[i+14], 15, -1416354905);
    b = II(b, c, d, a, m[i+ 5], 21, -57434055);
    a = II(a, b, c, d, m[i+12],  6,  1700485571);
    d = II(d, a, b, c, m[i+ 3], 10, -1894986606);
    c = II(c, d, a, b, m[i+10], 15, -1051523);
    b = II(b, c, d, a, m[i+ 1], 21, -2054922799);
    a = II(a, b, c, d, m[i+ 8],  6,  1873313359);
    d = II(d, a, b, c, m[i+15], 10, -30611744);
    c = II(c, d, a, b, m[i+ 6], 15, -1560198380);
    b = II(b, c, d, a, m[i+13], 21,  1309151649);
    a = II(a, b, c, d, m[i+ 4],  6, -145523070);
    d = II(d, a, b, c, m[i+11], 10, -1120210379);
    c = II(c, d, a, b, m[i+ 2], 15,  718787259);
    b = II(b, c, d, a, m[i+ 9], 21, -343485551);

    a = (a + aa) >>> 0;
    b = (b + bb) >>> 0;
    c = (c + cc) >>> 0;
    d = (d + dd) >>> 0;
  }

  return crypt.endian([a, b, c, d]);
};

// Auxiliary functions
md5._ff  = function (a, b, c, d, x, s, t) {
  var n = a + (b & c | ~b & d) + (x >>> 0) + t;
  return ((n << s) | (n >>> (32 - s))) + b;
};
md5._gg  = function (a, b, c, d, x, s, t) {
  var n = a + (b & d | c & ~d) + (x >>> 0) + t;
  return ((n << s) | (n >>> (32 - s))) + b;
};
md5._hh  = function (a, b, c, d, x, s, t) {
  var n = a + (b ^ c ^ d) + (x >>> 0) + t;
  return ((n << s) | (n >>> (32 - s))) + b;
};
md5._ii  = function (a, b, c, d, x, s, t) {
  var n = a + (c ^ (b | ~d)) + (x >>> 0) + t;
  return ((n << s) | (n >>> (32 - s))) + b;
};

// Package private blocksize
md5._blocksize = 16;
md5._digestsize = 16;

export default function (message, options) {
  if(typeof message == 'undefined')
    return;

  var digestbytes = crypt.wordsToBytes(md5(message, options));
  
  return options && options.asBytes ? digestbytes :
      options && options.asString ? bin.bytesToString(digestbytes) :
      crypt.bytesToHex(digestbytes);
};